The Government's long-promised plan to expand free GP care to all children is under threat in the wake of the worst ever trolley crisis in the country's overcrowded hospital wards.

The Government had hoped to expand the scheme, which is currently available to under-sixes, to all children under 12 by the end of this year and for all children during its terms in office.

But the scheme has been highlighted as one of the causes of the unprecedented backlog of patients waiting for treatment in cramped hospital wards.

Out-of-hours GP services have been overwhelmed by the number of parents seeking free medical care for their children over the Christmas period and this in turn has put massive pressure on hospitals.

The trolley controversy has all but signalled the end of free GP care for all children.

It is now expected that ministers will introduce reduced medical costs for children over six or expand the current scheme incrementally by one year at a time.

This would mean that if the Government survived a full term it would be able to roll out free GP care for children under 10 at most.

Speaking to the Irish Independent, Health Minister Simon Harris said he was committed to introducing free GP care for all children as was set out in the Programme for Government.

However, he said he would expand the scheme to under-12s only when he reached agreement with doctors on a new GP contract.

"We have to learn from the past and while I think the under-sixes scheme is very good and a benefit to lots of parents and families we need to make sure the GP system is supported to deal with any additional workload," Mr Harris said.

"That's why I made it very clear to the GPs when I took up office I would only be rolling out any new changes in the context of a new GP contract."

The negotiations between the Department of Health and GP representative bodies are due to commence this month.

Last night, the Irish Medical Organisation (IMO) warned that GP practices did not have the capacity to deal with a further influx of children availing of free medical treatment.

Chairman of the IMO's GP committee Dr Padraig McGarry said it would be "completely inappropriate" for Mr Harris to introduce free medical cards for under-12s when GPs were struggling to deal with demand under the current scheme.

"Given the current financial constraints in the health service I don't know where they would get the resources to meet the demands of expanding the scheme," he said.

The National Association of General Practitioners (NAGP) said the overcrowding crisis in hospital emergency departments had reached catastrophic levels owing to a lack of proper planning and investment. Separately, Mr Harris apologised for what hundreds of patients were going through.

Speaking at the Midland Regional Hospital in Tullamore, he said: "Our hospitals are going through an extraordinarily challenging period of time.

"I really am sorry for Irish patients and indeed for the staff working in our hospitals experiencing the conditions that they are having to put up with at the moment.